PB1446 - Direct oral anticoagulants for thromboprophylaxis in multiple myeloma – a systematic review and meta-analysis

Background: Multiple myeloma (MM) is associated with an increased venous thromboembolism (VTE) risk. The International Myeloma Working Group guideline recommends aspirin for low-risk patients and low molecular weight heparin for high-risk patients. Despite thromboprophylaxis, VTE rates remain high: a recent meta-analysis reported pooled rates as high as 6.2%. Although direct oral anticoagulants (DOAC) represent a promising alternative for these patients, a systematic evaluation of their efficacy and safety in MM is lacking.

Aims: To assess efficacy and safety of DOAC thromboprophylaxis in MM.

Methods: PubMed and EMBASE were systematically searched up to November 1st, 2022, for studies evaluating MM patients receiving DOAC thromboprophylaxis (PROSPERO: CRD42022376152). Two authors independently screened titles, abstracts and full texts, assessed bias using a modified version of the Newcastle Ottawa Scale, and performed data-extraction and -analysis. Outcome variables included VTE, bleeding, and all-cause mortality. Event rates were calculated using a one-sample random-effects meta-analysis with 0.5 continuity correction and logit transformation.

Results: Six articles comprising 399 patients on DOAC thromboprophylaxis were included, primarily involving newly diagnosed MM patients (53.9%), receiving immunomodulatory drugs (100.0%). Overall study quality was moderate (median 3, IQR 2.0; 4.5). Pooled VTE risk was 2.8% (95% CI, 1.4; 5.6) (figure 1). For bleeding, risk estimates were 7.6% (95% CI, 1.6; 30.2), 5.3% (95% CI, 2.2; 12.3) and 2.1% (95% CI, 1.0; 4.5) for minor-, clinically relevant non-major, and major bleeding, respectively (figure 2). Death rate could not be calculated due to limited data availability.

Conclusion(s): The estimated VTE risk was 2.8%. For bleeding, the risk estimates were 6.6%, 5.3% and 2.1%, for minor, CRNMB, and major bleeding, respectively. In MM patients on treatment, DOAC thromboprophylaxis resulted in lower VTE estimates. However, current evidence does not yet support routine DOACs use in MM patients. Further research is needed to establish the risk-benefit ratio of DOAC thromboprophylaxis in MM.